Narrative:

We were issued taxi instructions for runway 26L and the captain opted for a single engine taxi as the distance was substantial. I had just begun my taxi flows by selecting flaps 8 and was about to check the flight controls when the ground controller advised that runway 17 was available to us. The captain stated that I should decline; which I did; telling ground that we preferred to stay with 26L. As I returned to checking the flight controls; the captain then told me that he'd changed his mind and to let them know that we would; in fact; prefer runway 17. As I was communicating this new fact to the ground controller; I reviewed the taxi chart and; after looking outside; realized that we now had a very short taxi of only one or two hundred yards and I still had a considerable set of tasks to accomplish; including immediately starting the second engine. As I was starting the engine; I observed that the captain had pulled up the takeoff performance page on the FMS and was in the process of reviewing the new data pertaining to runway 17. As soon as the second engine start was complete; I went back to finishing my taxi flow by making a cabin announcement to the passengers and verifying a secure cabin with the flight attendants. Having accomplished that; I began our verbal review of the taxi checklist. First; however; I wanted to confirm with the captain that our flaps 8 setting was still correct after seeing him reviewing the FMS data for runway 17. I asked 'are you sure flaps 8 is still what we need'? And; he stated; 'yeah; flaps 8'. I had just began going through the verbal review of the taxi checklist when I heard the tower clear us for takeoff. I had not expected that to come so soon and; when I looked out ahead I noticed that we were about to cross the hold short line for 17. I was surprised by this because we had not yet fully completed the taxi checklist; had not reviewed the runway change checklist; and now still had to do the before takeoff checklist as well. I looked at the captain and asked him 'do you want me to tell him (tower) we need a little more time?' the captain said 'no; everything's set; just finish up the taxi and before takeoff checklists'. As I did that; we were already taking the runway. The takeoff appeared to be progressing normally through 80 knots. It was some time after that when I saw the captain move his right hand off the thrust levers and to the flaps selector; changing it from 8 to 20. It took me a moment to process what I was seeing and then I concluded that he must have realized that; perhaps; the FMS actually did indicate that 20 was required even though he had told me to leave them set at 8. By this time; I believe that we may have been at a very high speed and possibly nearing V-1. I had no idea what to say in this case other than 'shouldn't we abort'? But; before I could say anything; the captain quickly went to idle thrust and applied hard braking. I asked him what our issue was and he said that he noted a 'flaps misconfig' indication. I did not observe an indication of any malfunction; but that is not to say that it didn't happen. Perhaps he saw it; and I just didn't. Either way; that was no time to second guess; I just advised the tower that we had aborted due to an apparent abnormality and that we would be exiting the runway at the last turnoff. We did not return to the gate nor deplane passengers following the rejected takeoff. The captain made contact with operations and maintenance following the incident to determine what; if any; further action was necessary prior to resuming the flight. We did; however; remain on the ground for a significant period of time in order to allow the brakes to cool to an acceptable range.I believe that the above described incident could have; and should have been avoided by us if we had just stopped and taken the time to do a complete and unhurried review of checklists. While I was aware of this situation; I felt that I would at least mitigate it by respectfully reminding the captain of things like correct flaps settings; telling the tower we needed additional time; etc. I have been flying in this capacity for only two months however; so; beyond that; I was very reluctant to challenge anyone about anything. I now realize the importance of being more forceful while tactfully exercising my option to simply discontinue once I feel tasks aren't being accomplished in a safe and appropriate manner.

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Original NASA ASRS Text

Title: CRJ-900 First Officer reported the Captain rejected the takeoff just before V1 when he noticed the flaps were not set correctly for takeoff.

Narrative: We were issued taxi instructions for runway 26L and the Captain opted for a single engine taxi as the distance was substantial. I had just begun my taxi flows by selecting flaps 8 and was about to check the flight controls when the Ground Controller advised that runway 17 was available to us. The Captain stated that I should decline; which I did; telling Ground that we preferred to stay with 26L. As I returned to checking the flight controls; the Captain then told me that he'd changed his mind and to let them know that we would; in fact; prefer runway 17. As I was communicating this new fact to the Ground Controller; I reviewed the taxi chart and; after looking outside; realized that we now had a very short taxi of only one or two hundred yards and I still had a considerable set of tasks to accomplish; including immediately starting the second engine. As I was starting the engine; I observed that the Captain had pulled up the Takeoff Performance page on the FMS and was in the process of reviewing the new data pertaining to runway 17. As soon as the second engine start was complete; I went back to finishing my taxi flow by making a cabin announcement to the passengers and verifying a secure cabin with the flight attendants. Having accomplished that; I began our verbal review of the taxi checklist. First; however; I wanted to confirm with the Captain that our flaps 8 setting was still correct after seeing him reviewing the FMS data for runway 17. I asked 'are you sure flaps 8 is still what we need'? And; he stated; 'yeah; flaps 8'. I had just began going through the verbal review of the taxi checklist when I heard the tower clear us for takeoff. I had not expected that to come so soon and; when I looked out ahead I noticed that we were about to cross the hold short line for 17. I was surprised by this because we had not yet fully completed the taxi checklist; had not reviewed the runway change checklist; and now still had to do the before takeoff checklist as well. I looked at the Captain and asked him 'do you want me to tell him (Tower) we need a little more time?' The Captain said 'no; everything's set; just finish up the taxi and before takeoff checklists'. As I did that; we were already taking the runway. The takeoff appeared to be progressing normally through 80 knots. It was some time after that when I saw the Captain move his right hand off the thrust levers and to the flaps selector; changing it from 8 to 20. It took me a moment to process what I was seeing and then I concluded that he must have realized that; perhaps; the FMS actually did indicate that 20 was required even though he had told me to leave them set at 8. By this time; I believe that we may have been at a very high speed and possibly nearing V-1. I had no idea what to say in this case other than 'shouldn't we abort'? But; before I could say anything; the Captain quickly went to idle thrust and applied hard braking. I asked him what our issue was and he said that he noted a 'flaps misconfig' indication. I did not observe an indication of any malfunction; but that is not to say that it didn't happen. Perhaps he saw it; and I just didn't. Either way; that was no time to second guess; I just advised the Tower that we had aborted due to an apparent abnormality and that we would be exiting the runway at the last turnoff. We did not return to the gate nor deplane passengers following the rejected takeoff. The Captain made contact with operations and maintenance following the incident to determine what; if any; further action was necessary prior to resuming the flight. We did; however; remain on the ground for a significant period of time in order to allow the brakes to cool to an acceptable range.I believe that the above described incident could have; and should have been avoided by us if we had just stopped and taken the time to do a complete and unhurried review of checklists. While I was aware of this situation; I felt that I would at least mitigate it by respectfully reminding the Captain of things like correct flaps settings; telling the tower we needed additional time; etc. I have been flying in this capacity for only two months however; so; beyond that; I was very reluctant to challenge anyone about anything. I now realize the importance of being more forceful while tactfully exercising my option to simply discontinue once I feel tasks aren't being accomplished in a safe and appropriate manner.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.